638989 has 12 divisors (see below), whose sum is σ = 732000. Its totient is φ = 555984.

The previous prime is 638977. The next prime is 638993. The reversal of 638989 is 989836.

It is not a de Polignac number, because 638989 - 2⁷ = 638861 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638959) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3112 + ... + 3310.

It is an arithmetic number, because the mean of its divisors is an integer number (61000).

2⁶³⁸⁹⁸⁹ is an apocalyptic number.

It is an amenable number.

638989 is a deficient number, since it is larger than the sum of its proper divisors (93011).

638989 is a wasteful number, since it uses less digits than its factorization.

638989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 244 (or 231 counting only the distinct ones).

The product of its digits is 93312, while the sum is 43.

The square root of 638989 is about 799.3678752614. The cubic root of 638989 is about 86.1319859054.

The spelling of 638989 in words is "six hundred thirty-eight thousand, nine hundred eighty-nine".